de)s and 2,4-dioxo-1-imidazolidinecarbothioamides were prepared by the reaction of dimethyl 2-oxo-1,3-imidazolidinebis(carbodithioate) (1b) and methyl 2,4-dioxo-1-imidazolidinecarbodithioate (2b) with amines, respectively. The reaction of 2-oxazolidone with carbon disulfide gave 2-oxo-3-oxazolidinecarbodithioic acid, the methyl ester of which (4b) led to 2-oxo-3-oxazolidinecarbothioamides. Esters 1b